-3:
To many beginning players, slam bidding is all about Blackwood. In fact, Blackwood is only one tool among many, and, according to Easley Blackwood himself, his ace-asking convention is probably only appropriate on something like 25% of slam-zone hands.
Good slam bidding relies on setting trumps and establishing a game force while the bidding is still relatively low, and using the space below game as efficiently as possible. There are several specialized conventions to help, but the simplest and most often used is the cue-bid or control-showing bid: after trumps have been set and you are committed to game, bidding a side suit at your first chance to do so shows first round control (the ace or a void) in that suit; at your second chance, second round control (the king or a singleton.) The classic cuebidding situation is after 1-3:
shows the A
shows the A
shows the A
Suppose the auction begins 1 by you, 3(limit raise) by your partner. Since partner's strength is narrowly constrained, if your hand does not contain extra strength you can be completely certain slam is impossible. You can bid 4, regardless of which aces you do or do not have, and partner will pass, making 4 the final contract.
On the other hand, suppose the bidding begins 1 by you, 2 by your partner, 2 by you, 3 by your partner. Partner is unlimited, guaranteeing you have the values for game, but partner could have a monster and be waiting for information from you to decide which slam to bid. Therefore, even if you yourself are not interested in a slam, you should provide your partner with the requested information, (in this case, bidding 4 if you have the ace of clubs, for example.) If you raise 3 to 4 your partner will assume you have denied possession of a side-suit ace.
If your partner's hand is unlimited, and you can show a control without pushing the level of bidding higher, you are in what is called a mandatory cue-bidding situation. That is, because partner's hand is unlimited, you can't unilaterally decide that it is right to sign off.
Let's continue our hypothetical auction one round farther. Let's say it goes (with your opponents passing throughout) 1-2, 2-3, 4-4. What do your possible next bids mean?
: Mandatory cuebid. If you have the A, you must show it to your partner, whether you are interested in slam or not.
: This can mean you have a weak hand that lacks the ace of hearts (but may have other cuebiddable cards like the K or K) that is not sure the 5-level is safe. If you have a strong enough hand to be confident of making 5, however, you only bid 4 if you have no cuebiddable card.
: You promise the K (in addition to the A you showed with your 4C bid) and a good enough hand that the 5-level is safe even if your partner has the weakest hand consisted with his bidding so far.
: You promise the K (since partner has already shown the A) and a good enough hand that the 5-level is safe.
This is true of all bidding sequences. Think about what your partner's bid means, and also about what your partner could have bid but chose not to, and what that means.
To give a simple example, suppose the bidding starts 1-3-4. Now you hear your partner bid 4. Why 4 and not 4? The way most people use cuebids, you are entitled to assume your partner has the A but does not have the A.
Traditional cuebidding allows you some freedom in choosing which order to show controls. For instance, if you have both A and A in your own hand, after 1-3 the "obvious" bid is 4, but you know your partner is not going to respond with 4 since partner doesn't have the A, and you may find yourself forced all the way to 5 on your next turn. Some textbooks recommend you "lie" by bidding 4 first and 5 next, saving a step of bidding and making it easier for partner to show you a second-round diamond control. Others will claim that by bidding 4 first you deny the A,and when you bid 5 next, you are showing A and K.
This flexibility imposes a major limitation on the usefulness of standard cuebids. If you have no formal agreement on what order you show your controls, you are unable to deduce as much about your partner's hand.
The key difference between standard cuebids and the system I describe in Part II is the addition of a formal rule for which cuebid to make when holding several controls, which results in a very powerful and efficient way to show almost all the face cards in one's hand.